.calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
color: #333;
line-height: 1.6;
}
.calc-container {
background: #f9f9f9;
padding: 30px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
margin-bottom: 40px;
border: 1px solid #e1e1e1;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.form-group {
margin-bottom: 15px;
}
.form-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #2c3e50;
}
.form-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box; /* Ensure padding doesn't break width */
}
.form-group input:focus {
border-color: #3498db;
outline: none;
box-shadow: 0 0 5px rgba(52,152,219,0.3);
}
.calc-btn {
grid-column: 1 / -1;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.3s;
width: 100%;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #219150;
}
.result-box {
grid-column: 1 / -1;
background: #fff;
padding: 20px;
border-radius: 4px;
margin-top: 20px;
border-left: 5px solid #3498db;
display: none; /* Hidden by default */
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
color: #7f8c8d;
}
.result-value {
font-weight: bold;
font-size: 1.1em;
color: #2c3e50;
}
.big-total {
font-size: 1.5em;
color: #27ae60;
}
.seo-content h2 {
color: #2c3e50;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
margin-top: 30px;
}
.seo-content h3 {
color: #34495e;
margin-top: 25px;
}
.seo-content ul {
padding-left: 20px;
}
.seo-content li {
margin-bottom: 10px;
}
function calculateMortgage() {
// 1. Get Input Values
var homePrice = parseFloat(document.getElementById('homePrice').value);
var downPayment = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var loanTermYears = parseFloat(document.getElementById('loanTerm').value);
var propertyTaxYearly = parseFloat(document.getElementById('propertyTax').value);
var homeInsuranceYearly = parseFloat(document.getElementById('homeInsurance').value);
// 2. Validate Inputs
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTermYears)) {
alert("Please fill in all required fields (Price, Down Payment, Interest Rate, and Term) with valid numbers.");
return;
}
// Handle optional fields if empty
if (isNaN(propertyTaxYearly)) propertyTaxYearly = 0;
if (isNaN(homeInsuranceYearly)) homeInsuranceYearly = 0;
// 3. Perform Calculations
// Principal Loan Amount
var principal = homePrice – downPayment;
// Avoid negative principal
if (principal < 0) {
alert("Down payment cannot be greater than home price.");
return;
}
// Monthly Interest Rate (Annual / 100 / 12)
var monthlyInterestRate = (interestRate / 100) / 12;
// Total Number of Payments (Months)
var numberOfPayments = loanTermYears * 12;
// Calculate Monthly P&I
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyPrincipalInterest = 0;
if (interestRate === 0) {
monthlyPrincipalInterest = principal / numberOfPayments;
} else {
var x = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPrincipalInterest = (principal * x * monthlyInterestRate) / (x – 1);
}
// Calculate Monthly Tax and Insurance
var monthlyTax = propertyTaxYearly / 12;
var monthlyInsurance = homeInsuranceYearly / 12;
// Total Monthly Payment
var totalMonthlyPayment = monthlyPrincipalInterest + monthlyTax + monthlyInsurance;
// 4. Display Results
// Helper function to format currency
function formatMoney(amount) {
return "$" + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
document.getElementById('resPrincipalInterest').innerHTML = formatMoney(monthlyPrincipalInterest);
document.getElementById('resTax').innerHTML = formatMoney(monthlyTax);
document.getElementById('resInsurance').innerHTML = formatMoney(monthlyInsurance);
document.getElementById('resTotal').innerHTML = formatMoney(totalMonthlyPayment);
// Show the result box
document.getElementById('resultsArea').style.display = "block";
}
Mortgage Payment Calculator
Principal & Interest:
–
Monthly Property Tax:
–
Monthly Insurance:
–
TOTAL MONTHLY PAYMENT:
–
How to Calculate Your Mortgage Payments
Understanding the true cost of homeownership is crucial before signing on the dotted line. While many potential buyers focus solely on the listing price, the monthly financial commitment involves several components known collectively as PITI (Principal, Interest, Taxes, and Insurance). This calculator helps you break down these costs to provide a realistic estimate of your monthly housing budget.
The 4 Pillars of a Mortgage Payment (PITI)
To accurately calculate what you will pay every month, you must account for these four factors:
- Principal: The portion of your payment that goes directly toward paying down the loan balance. In the early years of a mortgage, this amount is small compared to interest.
- Interest: The fee charged by the lender for borrowing money. Your interest rate and loan term significantly impact how much you pay over the life of the loan.
- Taxes: Property taxes are assessed by your local government. These are typically paid annually but are often divided by 12 and collected monthly by your lender in an escrow account.
- Insurance: Homeowners insurance protects your property against damage. Like taxes, the annual premium is usually divided into monthly installments included in your mortgage payment.
The Calculation Formula
While this tool handles the heavy lifting instantly, the mathematical formula used by lenders to determine the Principal and Interest (P&I) portion of your payment is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
Where:
- M = Total monthly P&I payment
- P = Principal loan amount (Home Price minus Down Payment)
- i = Monthly interest rate (Annual Rate divided by 12)
- n = Number of payments (Loan Term in years multiplied by 12)
Why Your Down Payment Matters
The size of your down payment affects your monthly obligation in two ways. First, a larger down payment reduces the principal loan amount (P), which directly lowers the monthly payment. Second, putting down at least 20% often eliminates the need for Private Mortgage Insurance (PMI), a separate fee not included in standard PITI calculations but often required for low-down-payment loans.
Example Calculation
Let's assume you are purchasing a home for $400,000 with a 20% down payment ($80,000).
- Loan Amount: $320,000
- Interest Rate: 7.0%
- Term: 30 Years
Using the formula, your Principal and Interest payment would be approximately $2,129. If your annual property taxes are $5,000 and insurance is $1,200, your total monthly outlay would rise to roughly $2,645.